Acne is a common skin condition that occurs when hair follicles become plugged with oil and dead skin cells. It is an inflammatory disorder of the skin that has sebaceous (oil) glands that connect to the hair follicle, which contains a fine hair. In healthy skin, the sebaceous glands make sebum that empties onto the skin surface through the pore, which is an opening in the follicle. Keratinocytes, a type of skin cell, line the follicle. Normally, as the body sheds skin cells, the keratinocytes rise to the surface of the skin.

Acne can cause whiteheads, blackheads, pimples, and red, inflamed patches of skin such as cysts. It is most common among teenagers and young adults undergoing hormonal changes, but it can also occur during adulthood. Adult acne is more common among women and people assigned female at birth (AFAB) . Acne is caused when tiny holes in the skin, known as hair follicles, become blocked. Sebaceous glands are tiny glands found near the surface of your skin. The glands are attached to hair follicles.

There are different types of acne, including acne vulgaris, which is the medical name for common acne. Comedones, which are hair follicles that have become clogged with oil and dead skin cells, can develop into bumps called whiteheads and blackheads. Although mild acne may improve with over-the-counter treatments, more severe forms should be treated by a dermatologist. Products that may trigger comedones are called "comedogenic." Makeup labeled "noncomedogenic" is less likely to clog pores and contribute to acne.